System for automatically monitoring a motor vehicle

ABSTRACT

The invention relates to a system for automatically monitoring a motor vehicle, especially for automatically monitoring a vehicle (E) in a traffic jam. Said system comprises at least one sensor ( 2 ) for monitoring the space in front of the vehicle (E), and an electronic regulating device for regulating travel, braking and steering. According to the invention, said sensor is designed in such a way that it detects the movement of a vehicle (A) changing lanes in front of vehicle (E). The control of the vehicle is returned to the driver, or the driver is requested to regain control of the vehicle, when motor vehicle (E) shows a desire to follow the lane change of vehicle (A), and when it is determined, by means of the signals of the lateral sensor ( 8, 10 ), that during the monitoring, vehicle (E) is not at a sufficiently safe distance from a vehicle (B) detected by the lateral sensor. One such system for automatically monitoring a motor vehicle thus increases road safety in a simple manner.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to a system for automatic following-distancecontrol of a motor vehicle, in particular for automaticfollowing-distance control of a motor vehicle in a traffic jam, havingat least one sensor for monitoring the space in front of the vehicle,and an electronic device for regulating the travel, braking andsteering.

2. Related Art of the Invention

Automatic following-distance control is made possible by ACC (AutonomousCruise Control, sometimes also Adaptive Cruise Control) systems. An ACCsystem regulates the speed of a vehicle taking into account a vehicletraveling in front, and can under certain circumstances alsoautomatically follow its lane, i.e. change lane automatically.

DE 4313568 C discloses a method for providing assistance for a lanechange by a motor vehicle, a so-called lane change aid in which not onlythe space in front and behind are monitored but also the dead angle ismonitored by means of a radar system in the rear view mirror, and thedriver is provided, if appropriate, with warnings or instructions if heintends to change lane. In one development, the information from thelane change aid is used for a completely autonomous vehicle guidingsystem. A similar assistance-providing method which is improved by meansof satellite navigation and lane detection means is described in EP1052143 A.

ACC systems are described, for example, in the documents DE 19637245 A,WO 99/30920, WO 99/32318 and WO 00/62139. The three latter documentsalso relate to the problems with lane changing and overtaking operationswhich are made possible by suitable sensor and control systems. Adisadvantage is their complexity, not only owing to the expenditure oncontrol technology but also because the driver can only follow acomplicated control process with difficulty and therefore has to have“blind” faith in it.

SUMMARY OF THE INVENTION

The object of the invention is to provide a system for automaticfollowing-distance control, including automatic lane changes, whichoperates simply and reliably.

The object is achieved by means of a system having the features ofpatent claim 1.

The invention uses not only the known sensor system and signalprocessing means for following a vehicle but also one or two lateralsensors for monitoring the lateral space(s) behind the motor vehicle. Ifthe vehicle then follows a lane change of a vehicle traveling ahead, itis possible to use the signals of at least one of the lateral sensors todetermine whether the vehicle travels along a trajectory which describesthe lane change planned within the scope of the process of following thevehicle, without colliding with another vehicle which is located next tothe vehicle. In particular, by continuously determining the signals ofat least one of the lateral sensors, it is possible to detect if therelative position of a vehicle which is located adjacent to the driver'sown vehicle changes significantly; for example due to strongacceleration of the overtaken vehicle. It is therefore determined,through continuous measurement and calculation, whether the motorvehicle maintains, during the following-distance control, a reliabledistance from an adjacent vehicle sensed by at least one of the lateralsensors.

If a lateral sensor therefore signals that the motor vehicle undershootsa safe distance from an adjacent vehicle, the driver is preferablyrequested to assume control of the vehicle, or control of the vehicle isautomatically returned to the driver. This is also preferablyaccompanied by a warning signal. In addition, by means of the signals ofthe lateral sensor and data from automatic following-distance controlrelating to the traveling speed and route, it is already possible tocalculate in advance, before a safety distance is undershot, whether thevehicle will also maintain a safe distance from an adjacent vehicle inthe further course of the journey so that the transfer or handing overof control of the vehicle takes place as early as possible.

In the most favorable case, the invention restricts the manual controlof the vehicle to situations which can be reliably mastered only with avery high degree of complexity using a fully automatic system. Incontrast, the advantage that the driver can be certain of being able toimmediately receive or assume control of the vehicle in criticallane-changing situations is the predominant factor so that the driverdoes not experience a sense of helplessness with respect to theautomatic following-distance control.

Fully automatic following-distance control is relatively complicated andnot yet approved for road traffic. The invention permits a type ofsemiautomatic following-distance control in which the driver is involvedin lane changing situations which one would not wish to entrust to theautomatic system for safety reasons.

The invention is suitable for any type of automatic following-distancecontrol, and in particular as a system for following-distance control ina traffic jam.

BRIEF DESCRIPTION OF THE DRAWING

Further features and advantages of the invention emerge from thefollowing description of an exemplary embodiment with reference to thedrawing, in which, in plan views:

FIG. 1 shows a typical traffic situation with a switched-on automaticcontrol system for a vehicle in a traffic jam,

FIG. 2 shows a traffic situation when the vehicle traveling aheadchanges lane, and

FIG. 3 shows the situation from FIG. 2 with a motor vehicle which haslateral sensors.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a vehicle E with a system for automatic following-distancecontrol for a vehicle in a traffic jam, an automatic control system fora vehicle in a traffic jam, which relieves the driver in a traffic jam.For example, a system is known from the prior art and contains a sensor2 for monitoring the space in front of the vehicle, and an electronicdevice for regulating the travel, braking and steering, which is notshown. The sensor system for monitoring the space in front of thevehicle (sensor 2 and associated electronic system) is composed, forexample, of an image processing system, laser system or radar systemwith a monitoring angle β for the space in front of the vehicle.

The vehicle E, with a switched-on automatic system for controlling avehicle in a traffic jam, follows in a completely automatic fashion avehicle A which is traveling ahead, said vehicle E following along thetrajectory 4 on the left-hand lane of a two-lane road.

FIG. 2 illustrates what can happen when the vehicle A traveling aheadchanges lane from the left-hand lane to the right-hand lane. The vehicleE follows a trajectory 6 of the vehicle A which is calculated by thefollowing-distance control system, and owing to the limited monitoringangle β for the space in front of the vehicle it does not have anyknowledge of a vehicle B next to it on the right. This would result in acollision between the vehicles E and B if the vehicle E continues tofollow the vehicle A by also changing lane.

In the exemplary embodiment illustrated in FIG. 3, a lateral sensor 8,10 for monitoring the corresponding lateral rear space 12, 14 isaccommodated in each of the left-hand and right-hand rear view mirrorsof the vehicle E. Since motor vehicles are generally more than threemeters long, the monitored lateral rear spaces 12, 14 may possibly notneed to extend this far forward as shown in FIG. 3 if the monitoringangle β for the space in front of the vehicle is large enough.

In the situation illustrated in FIG. 3, the lateral sensor 10 senses thevehicle B in the right-hand lateral rear space 14. The driver of thevehicle E is warned or requested to assume control of the vehicle if thevehicle E will in future undershoot the safe distance from the adjacentvehicle B which is determined by calculation if said vehicle continuesto follow the vehicle A along the trajectory 6 calculated by thefollowing-distance control system. This criterion is appliedirrespective of whether or not there is a lane. This inventiverefinement of the system for automatically following a vehicle preventsa situation in which, for example owing to unpredictable acceleration ofthe observed vehicle B, a collision occurs with it during the subsequentlane change by a vehicle E.

Data from the automatic following-distance control can additionally beused in a particularly advantageous fashion for predictive determinationas to whether the distance from the vehicle B sensed by the lateralsensor will be undershot in future. This data is, for example, data froma navigation system which provides information about a bend lying aheadin the course of the carriageway, something which can significantlyaffect the shape of the trajectory 6. However, data from a trafficinformation system which provides information about traffic conditionsprevailing in the course of the carriageway lying ahead, such as atraffic jam, a traffic light at red or roadworks, can also have asignificant influence on future adaptations of the trajectory 6 and isto be taken into account by the system for automatic following-distancecontrol.

Within the scope of this application, the term lateral sensor [lacuna] asensor which covers the space about a motor vehicle E, in particular thespace next to it and the space behind it. Regions 12 and 14 for thecorresponding lateral sensors 8 and 10 are shown as examples of this inFIG. 3. However, it is not absolutely necessary for a lateral sensor tocover regions lying in front of the vehicle E, but it is alsoconceivable to embody said sensor in such a way that only the space tothe rear of the vehicle is covered (corresponding to a dead anglesensor).

The lateral sensor is particularly advantageously a sensor which canresolve its sensing range into a plurality of angular sections so that,depending on the resolution precision, it becomes possible to sense thedriving behavior of the vehicle B observed by the lateral sensor. Thebetter this driving behavior can be sensed, the better it is then alsopossible to determine whether a safe distance from the adjacent vehicleB will be undershot in future.

1. A system for automatic following-distance control of a motor vehicle,having at least one sensor for monitoring the space in front of thevehicle, an electronic device for regulating travel, braking andsteering, and at least one lateral sensor (8; 10) for monitoring alateral space (12; 14) behind the motor vehicle (E), the motor vehicle(E) following a vehicle (A) traveling ahead, wherein if the vehicle (A)performs a lane change and the vehicle (E) wishes to follow the lanechange, it is continuously determined in a predetermined fashion, on thebasis of signals of the lateral sensor (8; 10), whether, during thefollowing-distance control, the motor vehicle (E) will in futureundershoot a safe distance from a vehicle (B) which is sensed by thelateral sensor.
 2. The system for automatic following-distance controlas claimed in claim 1, wherein data from automatic following-distancecontrol is additionally used for determining whether the distance fromthe vehicle (B) sensed by the lateral sensor is undershot.
 3. The systemfor automatic following-distance control as claimed in claim 1, whereinthe driver is requested to assume control of the vehicle, or control ofthe vehicle is automatically returned to the driver if the motor vehiclewill undershoot a safe distance from a vehicle sensed by the lateralsensor.
 4. The system as claimed in claim 3, wherein the driver isadditionally warned.
 5. The system for automatic following-distancecontrol as claimed in claim 1, wherein the lateral sensor is a sensorwhich can resolve its sensing range into a plurality of angularsections.
 5. The system for automatic following-distance control asclaimed in claim 1, wherein said system is adapted for automaticfollowing-distance control of a motor vehicle in a traffic jam.